Powder mixture, use of the powder mixture, and a powder jet device

ABSTRACT

The present invention relates to a powder mixture, in particular for the remineralization of teeth, a powder jet device, in particular for application in the field of dentistry, a use of the powder mixture for producing a means for the remineralization of teeth and to a method for the remineralization of teeth, and a use of a powder mixture in a dental apparatus. The powder mixture comprises a deposition powder which is designed to adhere to tooth surfaces.

The present invention relates to a powder mixture, in particular for theremineralization of teeth, a powder jet device, in particular forapplication in the field of dentistry, a use of the powder mixture forproducing a means for the remineralization of teeth and to a method forthe remineralization of teeth, and a use of a powder mixture in a dentalapparatus.

Remineralization is a term used in dentistry meaning the redeposition ofdestroyed or lost minerals of tooth enamel after prior demineralization.Demineralization is the decalcification by loss of minerals. Thus,remineralization describes the redeposition of minerals into the toothenamel or the repair of minute enamel lesions. Caries formation in itsinitial phase can be stopped or healed through remineralization. Thiscan be achieved by the patient taking specific fluoride preparations orsuch. Also known in prior art are powders which can be depositioned onthe teeth to form a remineralization film. However, the prior art meansand methods have the disadvantage that the treatment is often unpleasantfor patients and also time-consuming. Furthermore, such remineralizationfilms do not adhere to the tooth surface.

It is therefore the object of the present invention to provide a powdermixture, in particular for the remineralization of teeth, a powder jetdevice, in particular for application in dentistry, a method ofremineralizing teeth, and a use of a powder mixture to produce anappropriate remineralization means or to use in a dental device whicheliminates the above mentioned disadvantages and is designed such thatit forms a stable remineralization film while providing the patient withmaximum comfort.

This object is achieved by a powder mixture according to Claim 1, by apowder jet device according to Claim 9, a method according to Claim 15,and appropriate uses according to Claims 14 and 16. Other advantages andcharacteristics of the invention are found in the subclaims and in thedescription.

The teaching of the invention relates to a powder mixture, in particularfor the remineralization of teeth, characterized in that the powdermixture comprises a deposition powder designed to adhere to the toothsurfaces. In particular, the powder mixture is designed to form aremineralization film on the tooth surfaces. Advantageously this allowsdecalcified tooth enamel to be re-enriched and hardened by thedeposition of new calcium phosphate. Furthermore, possibly exposeddentinal channels (dentinal tubules) can be closed up again. Thedentinal tubules conduct external stimuli such as hot, cold, sweet, souror contact to the dental nerve. This results in sensitive andhyper-sensitive teeth. According to the hydrodynamic theory described byBrännström (1966), this is caused by the movement of fluid within thedentinal tubules in response to the application of stimuli.Advantageously, the exposed dentinal tubules can be closed up again bythe remineralization or demineralization film. The powder mixture istherefore also designed to desensitize the teeth. For the sake ofclarity, the term ‘remineralization film’ will always be used here,which does not exclude that it can also—so to speak—be a desensitizingfilm.

Expediently, the remineralization film has a thickness between about 100nm and 2 μm. Such a film, or such a layer, is sufficient to closeexposed dentinal tubules and to form a remineralization film on theteeth which advantageously provides inter alia phosphate and calcium forremineralization processes. Such a remineralization film immediatelyrelieves the patients pain. No long-term treatment is necessary.Expediently, it is a powder mixture, i.e. a mixture which comprises atleast one component which advantageously is the deposition powder thatwill be explained in greater detail below. Advantageously, the powdermixture can be applied with a prior art powder jet device used for thecleaning of teeth. Expediently, such powder jet devices include a mixingchamber that can be filled with a powder which is then mixed with afluid, in particular with water, and with air and applied to, i.e.sprayed on the teeth.

Expediently, the powder mixture is characterized in that it contains acarrier powder which allows it to be applied to the tooth by means of apowder jet. Advantageously, the carrier powder is a cleaning powder, inparticular sodium bicarbonate, glycine, alditoles such as erythritol,calcium carbonate or a mixture of these substances. Preferably, thecarrier powder—so to speak—serves as a transport means for thedeposition powder. In case of a traditional powder jet device, aseparate nozzle or mixing arrangement would have to be constructed forthe fine deposition powder, since the very small particles of thedeposition powder are very difficult to diffuse into the air or to swirlin a mixing chamber or mixing arrangement. This makes application to thetooth surfaces extremely difficult.

Therefore, the powder mixture advantageously includes the carrierpowder. Expediently, the deposition powder can adhere to the carrierpowder, whereby the carrier powder is—so to speak—used as carrier mediumfor the deposition powder when the remineralization film is applied.Advantageously, the surface structure of the carrier powder or of theparticles of the carrier powder is designed such that the depositionpowder can adhere to it. Preferably, this adhesion already takes placein the production or in the mixing of the powder mixture and ismaintained while it is kept, for example, in a suitable container or inthe mixing chamber of the powder jet device. Preferably, the adhesion isdesigned such that it is maintained even when the powder mixture isapplied to the teeth, i.e. especially during the flight of the powdermixture. Advantageously, the deposition powder adheres to the carrierpowder. Also advantageously, the surface structure of the carrier powderis rugged to allow the deposition powder to adhere or to beincorporated. Furthermore, the carrier powder can provide a slipstreamfunction while being applied to the teeth. This can result in the bestspray conditions or flight conditions for the disposition powder.Expediently, this is achieved in that the average particle size of thecarrier powder is larger than the average particle size (or agglomeratesize) of the deposition powder. Thus, advantageously, a powder mixtureis provided which can be optimally applied to the tooth surfaces and canremain there for a long time with optimal adhesion.

Advantageously, the carrier powder is also a cleaning powder. Thus,advantageously, the powder mixture provides not only a depositionfunction but also a cleaning function. Prior cleaning of the toothsurfaces or the teeth in general is particularly advantageous, or undercertain circumstances even necessary to fully expose the dentinaltubules before they can be properly closed. It is therefore highlyadvantageous when the powder mixture provides a deposition function anda cleaning function to allow two different treatment methods, i.e. thecleaning of teeth and the deposition of the powder mixture, with thesame (powder jet) device.

The powder mixture according to the present invention is alsocharacterized in that the cleaning powder has a mean particle sizebetween 10 μm and 100 μm, preferably between 15 μm and 50 μm, and evenmore preferably at about 45 μm. For work in the subgingival region, themean particle size should not be greater than 45 μm, and preferably notgreater than 35 μm, and even more preferably between 10 μm and 30 μm.

Expediently, the powder mixture is characterized in that the powdermixture provides the cleaning function and/or the deposition function,and that the cleaning function and the deposition function can bechanged among the volume of fluid with which the powder mixture ismixed. Therefore, advantageously, the powder mixture is designed suchthat it can be mixed with a fluid, in particular with water. Only thenis it possible to achieve the high comfort level while the patient isbeing treated. Thus, it is certainly known in prior art to applyremineralization films to the teeth by means of a powder. However, thesecannot be mixed with water, or if they are mixed with water, they adherepoorly to the tooth surfaces. The water component allows the patient tobe comfortable during the treatment, since the mouth would become dryvery quickly when a dry powder is applied without water, and this wouldbe very unpleasant for the patient. Furthermore, it results in theformation of dust, which also limits the success of the treatment, sincethe operator cannot see the teeth and cannot tell which parts havealready been treated and which haven't. Advantageously, the powder jetcan also be focused with the water jet, since the water expedientlyencases the powder mixture while it is being diffused into the air.Advantageously, by the volume of the water and its proportion inrelation to the powder mixture, it can be switched between the cleaningfunction and the deposition function. Advantageously, the depositionfunction and the cleaning function are not provided separately. Bothfunctions are provided jointly by the powder mixture, but the powdermixture can also be adjusted, for example via the mixed water portion,such that either the deposition function or the cleaning functionpredominates. It is also possible to provide only the cleaning functionor only the deposition function. The invention is based on the principlethat the cleaning function predominates at higher water volumes and thedeposition function predominates at lower water volumes.

Preferably, the powder mixture is characterized in that the depositionmixture is a phosphate powder and that the proportion of the phosphatepowder in the powder mixture is preferably about 0.5% to 30%. Especiallypreferred is a proportion of about 2% to 5%. Advantageously, the powderportions mix readily with the fluid portion. Only that allows the powdermixture to adhere to the teeth and thus to form a remineralization filmwhile providing the greatest possible comfort for the patient.

Also preferably, the powder mixture is characterized in that thedeposition powder comprises agglomerates of nano particles and that anagglomerate has a specific surface area of approximately >50 m²/g,preferably >60 m²/g. Weak van der Waals forces are responsible forforming the agglomerates.

Preferably, the powder mixture is characterized in that it has anagglomerate size in the range between about 1 μm and 10 μm. Especiallypreferred is a size in a range between about 2 μm and 6 μm. The size isdefined as the diameter or a maximum length of the agglomerate(depending on its shape). Thus, the deposition powder comprises nanoparticles with a mean particle size in the range between about 50 nm and500 nm, preferably about 200 nm, which form agglomerates in the abovenamed magnitudes.

Preferably, the calcium/phosphate molar ratio in the preferred phosphatepowders is in the range between about 0.5 and 4, especially preferred ina range between 1 and 2.5, and even more preferred in a range betweenabout 1.5 and 1.8.

Preferably, the powder mixture is characterized in that the depositionpowder has hydroxylapatite, tricalcium phosphate and/or octocalciumphosphate. In other words, the already discussed phosphate powder ishydroxylapatite, tricalcium phosphate and/or octocalcium phosphate.Preferably, the hydroxylapatite, tricalcium phosphate and/or octocalciumphosphate is calcinated at about 1200° C. Naturally it is preferablethat the hydroxylapatite, tricalcium phosphate and/or octocalciumphosphate is in the form of the above named agglomerates of nanoparticles.

Expediently, the powder mixture is characterized in that the depositionpowder and/or the carrier powder is the carrier of medication and/orother additives. Preferably, an additive can for example be a colouringagent with which the colour of the remineralization film applied or tobe applied can be adjusted to the colour of the existing teeth.Naturally, the colour of the teeth can also be altered if desired, forexample whitened. The additives may include substances which promote orsupport the remineralization of teeth and protect the teeth againstother influences. Preferably, the powder mixture can be provided withdifferent taste varieties via at least one additive. Advantageously, anadditive can, for example, also be a colour marker which shows theoperator which regions of the teeth have already been treated.Expediently, the colour marker is designed such that it loses its colourafter a determinable time, in other words that it becomes invisibleagain to prevent the treated regions of the teeth becoming unnaturallycoloured.

According to the invention, a powder jet device, particularly for use indentistry, comprises a mixing unit and a control unit, whereby themixing unit is designed to produce a fluid/powder mixture from a fluidstream and/or an air stream and at least one powder, characterized inthat the powder jet device has a deposition function by which the powderjet device can form a remineralization film on tooth surfaces and thatthe formation of the remineralization can be influenced by the controlunit. Advantageously, the powder is the powder mixture according to theinvention.

Expediently, the mixing unit is designed to mix the powder mixture, thefluid stream, particularly a water stream, and/or an air stream. Alsopreferably, the mixing unit can be designed to mix the powder mixtureaccording to the invention, preferable consisting of a deposition powderand a carrier powder. Also preferably, the deposition powder can firstbe mixed with water or air and then with the carrier powder or viceversa. In principle, the difficulty is that the deposition powder isvery fine and difficult to swirl. It is therefore technically easier touse an already mixed powder mixture according to the invention.Expediently, the powder jet device comprises a manual device with aconnection to the fluid/powder mixture. Preferably, the powder jetdevice also comprises a stationary unit whereby the stationary unitcomprises a powder container to hold the powder mixture according to theinvention and is connected with the manual device via supply lines forair, water, powder mixture, etc. Advantageously, the powder container isdesigned to form the mixing unit. Also preferably, the powder jet devicecan be designed as a manual device which contains the powder containerand the mixing unit and is connected, for example via supply lines forair and water, with a stationary unit. In this case, the fluid/powdermixture is only formed in the manual device.

Advantageously, the powder jet device is characterized in that thecontrol unit influences the formation of the remineralization film viathe ratio of the fluid stream related to the portion of the powder orpowder mixture. Expediently, the powder is the powder mixture accordingto the invention, which contains a carrier powder. The less the controlunit regulates the water portion, the higher is the deposition function.If the carrier powder is a cleaning powder, the control unit canincrease the cleaning function by increasing the proportion of water,Advantageously, the switch can be automatic and is then indicated to theoperator of the powder jet device. Naturally, it is possible to switchdeliberately between cleaning function and deposition function (eitheronly cleaning or only applying a remineralization film). But bothfunctions can also be used simultaneously, whereby preferably, forexample, the portion of the cleaning function in relation to thedeposition function can be regulated via the fluid portion. As alreadyindicated, it is advantageous to perform the cleaning first and then toapply the remineralization film. The time necessary for each ispreferably calculated automatically by the control unit, whichexpediently is parametrizable in a suitable manner, for example byentering the size of the region or the number of teeth to be treated.The operator is then conveniently told when the cleaning can be ended orwhen the application of the remineralization film can begin, and for howlong the regions must be treated to achieve a remineralization film ofsufficient thickness.

Advantageously, the control unit can also automatically switch from thecleaning function to the deposition function. Expediently, the operatorcan also directly adjust the water portion via a control means such as arotary switch, an electronic control panel or an appropriatelyparametrized touch screen. Naturally, the above named characteristicsand advantages can analogously apply to increasing or decreasing thewater pressure which is naturally correlated with the amount of water.The same applies to air pressure which also influences the compositionof the fluid/powder mixture. Advantageously, the control unit is alsoprovided with an interval function which has the effect that thefluid/powder mixture is ejected at certain determinable intervals toform the remineralization film. Preferably, this is used to form aremineralization film of very even thickness. Thus, the interval can beexpediently adjusted such that ejection continues until aremineralization film of desired layer thickness is achieved. Duringthat time, the operator preferably holds the nozzle of the powder jetdevice in the same place of the tooth surface. When the interval hasended, the operator knows that the nozzle must now be slightly moved. Inthat fashion, the operator can treat a whole tooth or the tooth surfacesstep by step, thus achieving a layer of even thickness.

Preferable, the powder jet device is characterized in that the controlunit influences the formation of the remineralization film via pressure,temperature and/or application speed of the fluid/powder mixture. Whilebeing diffused into the air, the fluid/powder mixture possesses kineticenergy which is converted into heat when it hits the tooth surface. Thisheat is preferably utilized to form the remineralization film. In thenano second range, temperatures of about 500 to 600° C. can occur.Advantageously, this causes the nano particles or the agglomerates ofthe powder mixture to fuse together. Also advantageously, the heatcauses the particles or components to be deposited to the alreadyexisting remineralization film and to the tooth surface(s).

Naturally, an increase in pressure (of the air stream as well as thewater stream) can change the kinetic energy of the fluid/powder mixture,which means that the formation of the remineralization film can beinfluenced. This also applies to the increase or decrease in thetemperature or speed of the fluid/powder mixture.

Expediently, the powder jet device is characterized in that the powderjet device has a cleaning function, whereby the fluid stream for thecleaning function is preferably >20 ml/min, and the fluid stream for thedeposition function is preferable about 2 to 10 ml/mm.

Also preferably, the powder jet device is characterized in that it canbe switched between the deposition function and the cleaning function.It is advantageous when two defined amounts of water or water portionsare provided, between which the device can be switched. When switchingbetween cleaning function and deposition function, it is also possiblein addition or alternatively to regulate the amount of powder and/or thepressure of the device. Higher air pressure promotes the cleaningeffect.

According to a preferred embodiment of the invention, the device isexclusively switched between the two operating states(cleaning/deposition) by reducing or increasing the amount of liquid orfluid. Preferably, the powder jet device can be designed such that thetwo operating states can be pre-set and that the operator only switchesbetween the two operating states during treatment, depending on whichfunction is required.

Thus, advantageously, the powder jet device is characterized in that thepowder jet device has one predeterminable operating state for depositionand that the powder jet device has one predeterminable operating statefor cleaning, and that the powder jet device can be switched back andforth between these two predetermined operating states.

Also advantageously, the powder jet device is characterized in that thepowder jet device is provided with a heating arrangement for preheatingthe powder. Preferably, this can be used to influence the formation ofthe remineralization film. The above mentioned effects (concerning theinfluence of temperatures) were already described. Naturally, the fluidstream can also be preheated.

Expediently, the powder jet device is also equipped with a light sourcewhich provides a light ray that illuminates the tooth region beingtreated at the moment. Thus, the operator knows in which region theremineralization film is being applied or which region is being cleaned.This allows for a remineralization film layer of particularly eventhickness.

The invention also relates to a suitable means for remineralizing toothsurfaces. This means is produced by using the powder mixture accordingto the invention plus optionally other components as for example finelygrained substances such as silica gel, bleaches, analgetics,bactericides or flavourings added to the means. Air and water can alsobe added to the means to enable it to be applied to the tooth surfacestreated with the powder jet device.

According to the invention, a method of remineralizing teeth comprisesthe steps of:

-   -   providing a powder or powder mixture;    -   providing a fluid stream and/or air stream;    -   mixing the fluid stream and/or air stream with the powder or        powder mixture to form a fluid/powder mixture;    -   depositing the fluid/powder mixture onto the teeth;    -   controlling the deposition by adjusting a ratio between the        fluid stream and the powder or powder mixture.

Preferably, the method also comprises the step of:

-   -   cleaning the teeth.

According to the invention, the powder mixture is preferably usedtogether with a fluid, preferably water, in a medical device, inparticular a dental powder jet device, to clean and remineralize teeth,whereby it is possible to switch between the cleaning function and thedeposition function of the powder mixture via the amount of fluid withwhich the powder mixture can be mixed.

Naturally, the above named advantages and characteristics of the powdermixture according to the invention also apply to the powder jet deviceaccording to the invention, the method according to the invention andthe use according to the invention as well as to any combinationthereof.

1. A powder mixture, in particular for the remineralization of teeth,characterized in that the powder mixture comprises a deposition powderdesigned to adhere to tooth surfaces.
 2. The powder mixture according toclaim 1, characterized in that the powder mixture comprises a carrierpowder and that the carrier powder is a cleaning powder, in particularsodium carbonate, glycine, alditoles such as erythritol, or calciumcarbonate.
 3. The powder mixture according to claim 2, characterized inthat the cleaning powder has a mean particle size ranging between 10 μmand 100 μm.
 4. The powder mixture according to claim 1, 2 or 3,characterized in that the powder mixture offers a cleaning function anda deposition function, whereby the deposition function serves toremineralize the teeth.
 5. The powder mixture according to one of thepreceding claims, characterized in that the deposition powder is aphosphate powder, and that the portion of the phosphate powder in thepowder mixture is preferably between about 0.5% and 30%.
 6. The powdermixture according to one of the preceding claims, characterized in thatthe deposition powder comprises agglomerates of nano particles and thatan agglomerate has a specific surface area of approximately >50 m²/g. 6.The powder mixture according to claim 6, characterized in that a size ofthe agglomerate is in the range between approximately 1 μm and 10 μm. 8.The powder mixture according to one of the preceding claims,characterized in that the calcium/phosphate molar ratio of thedeposition powder is in the range between approximately 0.5 and
 4. 9.The powder mixture according to one of the preceding claims,characterized in that the deposition powder comprises hydroxylapatite,tricalcium phosphate and/or octocalcium phosphate.
 10. The powdermixture according to one of the preceding claims, characterized in thatthe deposition powder and/or the carrier powder is a carrier ofmedication and/or other additives.
 11. A powder jet device, inparticular for use in dentistry, comprising a mixer unit and a controlunit, whereby the mixer unit is designed to produce a fluid/powdermixture consisting of a fluid stream and/or an air stream and at leastone powder or powder mixture, characterized in that the powder jetdevice has a deposition function by which the powder jet device can forma remineralization film on tooth surfaces, and which can be influencedby the control unit in forming the remineralization film.
 12. The powderjet device according to claim 11, characterized in that the control unitinfluences the formation of the remineralization film via the ratiobetween the fluid stream and the portion of the powder or powdermixture.
 13. The powder jet device according to one of claims 11-12,characterized in that the powder jet device has a cleaning function,whereby the fluid stream for the cleaning function is preferably >20ml/min, and whereby the fluid stream for the deposition function ispreferably about 2 to 10 ml/min.
 14. The powder jet device according toone of claims 11-13, characterized in that it can be switched back andforth between the deposition function and the cleaning function.
 15. Thepowder jet device according to one of claims 11-14, characterized inthat the powder jet device has a determinable operating state for thedeposition function and that the powder jet device has a determinableoperating state for the cleaning function, and that the powder jetdevice can be switched back and forth between the two pre-set operatingstates.
 16. The powder jet device according to one of claims 11-15,characterized in that the powder jet device has a heating arrangementfor preheating the powder or powder mixture.
 17. Use of a powder mixtureaccording to one of claims 1-10, if applicable, together with otherfinely grained substances such as silica gel, bleaches, analgetics,bactericides and/or flavourings, to produce a means for remineralizingteeth.
 18. A method for the remineralization of teeth, comprising thesteps of: providing a powder or powder mixture; providing a fluid streamand/or air stream; mixing the fluid stream and/or air stream with thepowder or powder mixture to form a fluid/powder mixture; depositing thefluid/powder mixture onto the teeth; controlling the deposition byadjusting a ratio between the fluid stream and the powder or powdermixture.
 19. The use of a powder mixture according to one of claims 1 to10 with a fluid, preferably water, in a medical device, in particular ina dental powder jet device, for cleaning and remineralizing teeth,characterized in that it is possible to switch between the cleaningfunction and the deposition function of the powder mixture via theamount of fluid with which the powder mixture can be mixed.